Abstract/Description

The aim of the current simulation study was to maximise the amount (kg) of high value meat arising from surplus males and females per kilogram of the goat population and, maximise weight gains to turnoff age. Subsequently, the study aimed to decrease turnoff age, maximisation of reproduction rates and minimisation of the mature weight of does in the low-input livestock production system in Kenya. Three crossbreeding systems and a synthetic breed development were evaluated, namely; (a) straight breeding system that utilised pure Small East African goat (SEAG) where parental lines were maintained to generate the desired terminal crosses, (b) three-breed crossbreeding system that utilised SEAG as pure breed, Galla goat (GG) as the first cross sire breed, and Improved Boer goat (IBG) as the terminal sire, (c) two-breed rotational crossbreeding system where the SEAG and IBG were purebreds, and (d) synthetic breed development system utilising SEAG X IBG. The HotCross crossbreeding simulation software was used to assess the predicted performance of the different goat breed crosses under conditions of agro ecological zones (AEZ) V and VI. A model was developed to compare these crossbreeding systems, and showed the optimum numbers required in each stage of a cross to maximise production. In the AEZ V, it was found that the three breed terminal system gave 18.2 kg (76%) improvement over straightbreds per doe mated per year. The multi-breed composite realised 20.4 kg (86%) improvement over pure SEAG. In the AEZ VI, it was found that the three breed terminal system gave 10 kg (64%) improvement over straightbreds per doe mated per year. The multi-breed composite realised 14.6 kg (94%) improvement straightbreds per doe mated per year. The two breed rotation was worse than the multi-breed composite in both environments. This implies that in low-input livestock production system, a multi-breed composite may be the crossbreeding system of choice, so long as supportive infrastructure is put in place.